(1) Field of the Invention
The present invention relates to the taking of measurements in an operating furnace and particularly to the sampling of gases and/or the measuring of temperature at points along a radius of a blast furnace. More specifically, this invention is directed to furnace condition sampling probes and especially to supports for such probes which facilitate the use thereof and effectively extend the length thereof. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
(2) Description of the Prior Art
In order for a blast furnace, particularly a modern furnace which operates with a comparatively high pressure, to be operated so as to obtain the optimum results, it is essential to monitor conditions within the furnace. The conditions which are desirably monitored include the chemical composition of the gases produced and the temperature profile across the furnace charge. These conditions are sensed through the use of probes which may be inserted into the furnace, both above and into the charge, to collect gas samples and take temperature measurements. An example of a furnace probe may be seen by reference to U.S. Pat. No. 3,888,123.
In the case of a blast furnace, the probes are introduced horizontally via apertures provided in the lateral wall of the furnace. The wall of a blast furnace will consist of an outer metal shell or armouring and an inner lining of refractory material. As may be seen from U.S. Pat. No. 3,888,123, it has been prior practice to provide a support for a blast furnace probe on the outside of the shell. In order to obtain information which is as complete and accurate as possible the probe must be extended into the furnace to the region of the central axis thereof. Accordingly, a typical furnace probe may have a length of as much as 8 meters and, with a very large capacity furnace, the probe length could be even greater. This length, coupled with the fact that a furnace probe must of necessity be of comparatively heavy construction in order to withstand the harsh operating environment to which it is exposed, makes it difficult to provide adequate support.
As noted above, the practice in the prior art has been to support a furnace probe solely from a flange affixed to the exterior of the furnace shell. Accordingly, as the probe is extended into the furnace, it will deform under the effects of its own weight and the probe may also be caused to further deform or be deflected from the horizontal as a result of contact with the furnace charge material and particularly descending charge material. All of the stresses to which the probe is exposed will be concentrated at the point where the probe is supported and the magnitude of these concentrated stresses will be a function of the unsupported length of the probe in the furnace. The concentrated stresses at the support point will, of course, increase the friction between the probe and support and thus impede the movement of the probe. Accordingly, significant force is required to extend and retract the probe and the friction causes wear on the probe and the support.